1. Field of the Invention
The invention relates generally to powered endoscopic cutting devices. More particularly, the invention relates to rotating shaver systems for use in various endoscopic surgical procedures. Still more particularly, the invention relates to rotating burrs and their method of use in endoscopic surgical procedures at non-fluid filled surgical work sites.
2. Description of the Prior Art
The use of elongated surgical cutting instruments has become well accepted in performing closed surgery such as arthroscopic or, more generally, endoscopic surgery. In closed surgery, access to the surgical site is gained via one or more portals, and instruments and scopes used in the surgical procedure must be elongated to permit the distal ends of the instruments and cameras to reach the surgical site. Some conventional surgical cutting instruments (shavers) for use in closed surgery are rotary powered and have a straight, elongated outer tubular member and a straight, elongated inner tubular member concentrically disposed in the outer tubular member. The inner and outer members both separately and jointly are sometimes referred to in the art as "blades" and are usually disposable. The outer member has a distal end having an opening in the end or side wall (or both) to form a cutting port or window and the inner member has a distal end disposed adjacent the opening in the distal end of the outer member. The inner member is (usually) easily insertable into and removable from the outer member to facilitate cleaning or interchanging parts. Each of the elongated members has a hub or termination at its proximal end in order to attach the components to a rotary drive means within a reusable handpiece. The distal end of the inner tubular member has a cutting means or cutting edge for engaging tissue via the opening in the distal end of the outer tubular member. In many cases (but not all) this distal cutting means cooperates with the opening in the outer member to shear, cut or trim tissue. In some cases, such as burrs, the opening in the outer member merely allows access to the tissue and does not otherwise cooperate with the cutting means. The term "cutting edge" or "cutting means" as used herein is intended to include abrading (e.g. burrs) and other devices whether or not there is any traditional cutting or shaving action and whether or not there is any cooperative shearing action. The inner tubular member is rotatably driven about its axis from its proximal end, normally via a handpiece having a small electric motor which is controlled by either finger actuated switches on the handpiece, a foot switch or switches on a console supplying power to the handpiece. The distal end of the various styles of inner tubular members can have various configurations depending upon the surgical procedure to be performed, and the opening in the distal end of the outer tubular member would then have a configuration adapted to cooperate with the particular configuration of the distal end on the inner tubular member. For example, the inner and outer tubular members can be configured to produce whisker cutting, synovial resection, arthroplasty burring or abrading, side cutting, meniscus cutting, trimming, full radius resection, end cutting and the like, and the various configurations are referred to generally as cutting means.
The aforementioned elongated surgical cutting instruments have also been produced in angled configurations in which the axes of the distal tips of the inner and outer members are aligned and offset or bent at a fixed angle relative to the axes of the proximal ends of the aligned inner and outer members. Examples of such fixed-angle, rotary surgical instruments are shown in U.S. Pat. No. 4,646,738 (Trott), assigned to the assignee hereof, and in European Patent Application 0 445 918 (Krause et al.). In other respects the operation of these fixed-angle shavers is largely the same as that of the straight shavers described above. Known fixed-angle shavers are generally produced with only one degree of bend--usually 15.degree.. Recently a variable-angle (i.e. bendable) rotary shaver system has been introduced and is described in U.S. Pat. No. 5,411,514 (Fucci et al.), assigned to the assignee hereof, in which the outer tube may be bent by a user to a user-selected angle while still enabling the inner tube to be selectively inserted into and removed from the outer tube. The inner member of this device has a hollow plastic body and a metallic distal tip into which a cutting edge is formed. In all of these devices, the loose tissue resulting from the cutting, resecting or abrading procedure may be aspirated through the hollow lumen of the inner tubular member to be collected via a vacuum tube communicating with the handpiece. The devices are generally used in an aspiration-only mode since the surgical site is usually distended by some fluid medium.
However, during certain surgical procedures there is no fluid medium surrounding the work site and it is desirable to introduce irrigating fluid to the surgical site in order to simply irrigate the site to improve visualization or to facilitate the aspiration of debris. Such irrigation is usually provided by separate instruments generally known as irrigation/aspiration devices which can be used to either irrigate or aspirate a site. Recently, powered endoscopic surgical cutting devices have been produced in order to simultaneously provide irrigation and aspiration without the necessity of using a separate instrument.
One known device described in U.S. Pat. No. 5,782,795 (Bays) comprises a rotating shaver blade having a separate fluid tube secured to the outside of the outer tubular member. The proximal end of the tube is connected to a source of fluid supply and the distal end of the tube is joined to a fluid port formed in the distal end of the outer tubular member. Fluid is cyclically permitted to flow into the inner tubular member when the inner cutting window faces the fluid port.
Another known irrigating shaver blade assembly utilizes a dual-lumen plug to connect a rotating shaver blade to a fluid source. One lumen of the plug permits fluid to flow into the space between the inner and outer tubular members and the other lumen permits aspiration through the lumen of the inner member.
Another known irrigating shaver blade assembly described in a co-pending application assigned to the assignee hereof and incorporated by reference herein, comprises a shaver blade assembly in which the outer tubular member is provided with a fluid inlet port which is selectively engageable with a fluid adapter. The fluid adapter can communicate irrigating fluid from a fluid source through the fluid inlet port and an elongated channel between the inner and outer tubular members.
None of the known irrigating shaver blade assemblies is provided with a burr at the distal tip of the inner member. In non-fluid filled surgical work sites the use of a burr against hard tissue such as bone tends to create bone dust and other tissue debris which can obscure visualization of the work site through an associated endoscope.
It is accordingly an object of this invention to produce a rotating shaver assembly having a burr at the distal end of the inner member and fluid channel means for communicating irrigating fluid to the distal end of the device.
It is also an object of this invention to produce such an irrigated burr without increasing the diameter of the outer member of the shaver assembly by utilizing an external fluid conduit.